FAULTY windscreen wipers are enough to make a car fail its MoT, says the AA, which urges drivers to make regular checks on their wipers and to replace them once a year.

In the early days of motoring, drivers used a sliced potato to clean their windscreens. Today, the design of modern wiper blades takes into account aerodynamics, temperature changes and windscreen sizes, but even these hi-tech blades won't keep a screen clean if they're past their best, the AA warns.

Steve Dewey, director of AA Service Centres, said: "When it comes to car maintenance, wiper blades are easy to overlook, but they are vital for safe driving. Neglecting them can be dangerous and, because they are so crucial to visibility in the wet, faulty blades could mean an MoT failure."

Blades can become damaged even if the car isn't used. In winter, the rubber can become frozen to the windscreen and in summer the surface temperature of the glass can reach up to 80C, both of which can affect the performance of the blade.

When leaving the car parked in frosty weather, the wipers should be switched off, as ice forms on the blades and the rubber can be damaged or the wiper motor overheated when the ignition is switched on again.

There are several tell-tale signs that show it's time to change blades, like jerking or making a noise; smears and unwashed areas on the windscreen; and cracked or worn rubber on the blade. Wipers should contact evenly along their length and the blades must be securely attached. Only the rubber blade edge should contact the glass, otherwise the windscreen will be damaged.

Drivers should also ensure their car's windscreen washer bottle is topped up. Windscreens and windows should be regularly cleaned both inside and out, too. If it snows, drivers should clear the roof before setting off as the snow can fall onto the windscreen obscuring the view.

For details of AA Service Centres in the South, call 08457 361 361.